a) Field of the Invention
The invention concerns a wheel-assembly monitor to diagnose passing train-cars for the purpose of detecting the temperature of the wheel-assembly axles, drive, braking and bearing components, and of other heat sources to be monitored on train-cars, in particular radiation sources supplied with heat by conduction from moving parts which are only indirectly accessible, or whereby the temperatures of these components can be inferred.
b) Description of Related Art
Infrared detection systems are used in railroad systems for monitoring heat sources. These systems are affixed to concrete foundations or to the railroad ties or rails and, in order to retain enough train clearance, they must be mounted outside the space subtended between the two rails; the track being formed by two rails supported by cross-ties.
The known detection systems, however, suffer from substantial drawbacks regarding the required number of track switches, the mandatory mountings, the susceptibility of mechanical and electrical influences, the constancy of detection configuration, the detectable wheel-assembly or components for one system per axle, and the electrical safety consideration of possible contact between the life-endangering voltages and the housings of the monitors.
Detection geometries subtending slopes &gt;90.degree. must be used with the conventional monitors mounted between the wheels of one assembly. This requires at least one additional track switch to define the measurement range. Moreover, the fixed measurement ranges can be only covered if, for instance, electromagnetic or eddy rail-brakes are in a position other than lowered, i.e. not in a braking position. Additionally, when the sun is low, its light may fall onto the system; triggering false alarms during train travel.
The mounting of the monitor weighing up to 50 kg to the rail, tie or concrete foundation is exceedingly laborious. The systems mounted to the rails or ties are susceptible to frequent mechanical disturbances and accordingly operation is reduced while maintenance is increased.
In such systems incurring vibrations or mechanical impacts for instance from parts loaded on and/or overhanging the cars, the measurement geometry of the monitor may be imperceptibly degraded and operational reliability may also be jeopardized. Therefore, plate guards must be installed to protect the monitors, as a result of which maintenance is substantially increase. In order to allow cable exchange even in times of frost, the cables are usually mounted off ground and on the superstructure. Hence such electrical connections are also frequently damaged.
Electrical safety against excessive high voltages (to the touch) heretofore could only be assured for the 220-volt rail-affixed monitors and for track layouts fitted with all-clear displays by using a detector connected to the particular rail. If ground is lost and the infrared detector housing is at voltage, the maintenance personnel is in lethal danger.